"Warning: This may make you cry. The Final Season, 2019. #OITNB," the caption said.

The cast thanked their fans and said goodbye to the series which launched on Netflix in 2013.

"I'm so grateful for the fun times, the knowledge, the friendships, the love, the family that we have created together," Aduba said. "Season 7 you will not be disappointed. It is a season you will not forget and we're going to give you everything and more that you could have ever wanted."

Orange is the New Black, from creator Jenji Kohan, is based on Piper Kerman's memoir Orange is the New Black: My Year in a Women's Prison.

Season 6, which premiered in July, ended with Piper being released from Litchfield Penitentiary.